Instrumental and Sensory Characterization of Heat-Induced Odorants in Aseptically Packaged Soy Milk

Abstract

Predominant heat-induced odorants generated in soy milk by ultrahigh-temperature (UHT) processing were evaluated by sensory and instrumental techniques. Soy milks processed by UHT (143 degrees C/14 s, 143 degrees C/59 s, 154 degrees C/29 s) were compared to a control soy milk (90 degrees C/10 min) after 0, 1, and 7 days of storage (4.4 +/- 1 degrees C). Dynamic headspace dilution analysis (DHDA) and solvent-assisted flavor evaporation (SAFE) in conjunction with GC-olfactometry (GCO)/aroma extract dilution techniques and GC-MS were used to identify and quantify major aroma-active compounds. Sensory results revealed that intensities of overall aroma and sulfur and sweet aromatic flavors were affected by the processing conditions. Odorants mainly responsible for the changes in sulfur perception were methional, methanethiol, and dimethyl sulfide. Increases in 2-acetyl-1-pyrroline, 2-acetyl-thiazole, and 2-acetyl-2-thiazoline intensities were associated with roasted aromas. A marginal increase in intensity of sweet aromatic flavor could be explained by increases in 2,3-butanedione, 3-hydroxy-2-butanone, beta-damascenone, and 2- and 3-methylbutanal. Predominant lipid-derived odorants, including (E,E)-2,4-nonadienal, (E,E)-2,4-decadienal, (E,Z)-2,4-decadienal, (E)-2-nonenal, (E)-2-octenal, 1-octen-3-one, 1-octen-3-ol, and (E,Z)-2,6-nonadienal, were affected by processing conditions. Intensities of overall aroma and sulfur notes in soy milk decreased during storage, whereas other sensory attributes did not change. Color changes, evaluated by using a Chroma-meter, indicated all UHT heating conditions used in this study generated a more yellow and saturated color in soy milk in comparison to the control soy milk.

The Significance of Volatile Sulfur Compounds in Food Flavors

“…Additionally, dimethyl sulfide was reported as one of the significant flavor components of UHT milk off-flavor (143). Methional, methanethiol, and dimethyl sulfide are the source of "sulfur" and "cooked" off flavors in ultrahigh-temperature (UHT) processed soy milks (144).…”

HS-SPME/GC-MS and chemometrics for volatile composition of Chinese traditional aromatic vinegar in the Zhenjiang region

“…Among these carbonyl compounds, 2,3-butanedione and 3-hydroxy-2-butanone were detected in all Zhenjiang aromatic vinegars, with the concentration of 20-4440 mg/L and 130-5700 mg/L, respectively (Table 3). 2,3-Butanedione and 3-hydroxy-2-butanone were detected and are responsible for the buttery flavour as well as caramel and fruity odour in red wine vinegar (25)(26)(27). The compound 2,3-butanedione was the most important precursors of alkylpyrazine (28,29).…”

Volatile sampling by headspace techniques

“…All include as main parts a sample vessel, a trap and different devices (e.g., flow-pressure regulators, valves, and probes) for regulation and control of purge gas and temperature throughout the whole system. A few extractors also offer the ability to dry purge the trap after the purge step to remove water that may have accompanied target volatiles during this step and which, e.g., can block the flow of gas (if condensed in cold traps), or destabilize the GC stationary phase [45,46]. Furthermore, several instruments allow, after thermal desorption of the retention trap (primary trap), a secondary trapping of volatiles by cryofocusing before injection onto the GC.…”

“…Lozano et al [45] evaluated by sensory and instrumental methods the heat-induced odorants in ultrahigh-temperature (UHT)-processed soy milk. D-HS dilution analysis (DHDA) and solvent-assisted flavor evaporation (SAFE) were selected as complementary techniques to fractionate the wide range of aroma-active volatiles present in this sample (for experimental conditions, see Table 2).…”